Department of Mechanical Engineering R.V. College of Engineering Mysore Road, Bangalore-59
Subject Seminar Report GREEN TECHNOLOGY-
gSOLAR POWER TOWERSh
Prepared & Presented by
Student Name
: NIKHIL
HEGDE
USN
: 1RV06ME064
Section & Semester
: 8th SEM , B CERTIFICATE
Department of Mechanical Engineering R.V. College of Engineering Bangalore-560059
This is to certify that the seminar titled Green Technology-SOLAR POWER TOWERS has been carried out by NIKHIL HEGDE USN 1RV06ME064 th
As a part of the 8 semester curriculum in Bachelor of Engineering in Mechanical Engineering from VTU during the Academic year 2009-10.
Dr. B. Anand
Professor and Head, Department of Mechanical Engineering R. V. College of Engineering Bangalore-560059
SYNOPSIS
GREEN TECHNOLOGY
(SOLAR POWER TOWERS)
Introduction:
Green technology is related to technological advances made in the field of power ge neration from non conventional energy source that are considered to be environmentally friendly and non polluting.Every form of energy collection will result in some pollution but those that are green are known to cause less than those that are not.Green house gases ,a byproduct of traditional sources of energy such as fossil fuels are said to be causing global warm ing at an accelerated pace and hence there is a need to focus on technology that is environmentally fri endly and also economically feasible. Global issues:
The United Nations Energy Organization tags fossil fuels as elimentary energy/conventional energy.Electricity is merely a secondary energy derived from these sources.At present the energy consumed all over the world relies mainly on five main energy sources like coal,petroleum,natural gas,water and nuclear energy.The consumption of petroleum constitutes approximately 60% of energy used from all sources. Statistics show that daily consumption of petroleum is 40 million barrels of which 50% is for au tomobile use.In accordance with this calculation,as fuels are burnt poisonous materials such as 500 mill ion tonnes of carbon monoxide,100 million tonnes of hydrocarbons,550 million tonnes of carbon and 50 million tonnes of nitrogen oxides are emitted into atmosphere every year causing Green House Effect.
It can be classified under -
First generation technologies are most competitive in locations with abundant resources.Their future depends on exploration of available resource potential particularly in developing countries and on overcoming challenges related to environment and social acceptance. Example:-hydroelectric plants,geo thermal power plants and biomass briquettes.
Second generation technologies are said to be the future of power generation and is fast catching up but the market for these sources are limited to only a few countries.Example:- solar heating systems,use of ethanol,etc
Third generation technologies are not yet widely demonstrated or commercialised.They are on the horizon and may have potentional comparable to other renewable energy technologies but still depend on attracting suffecient attention and R&D funding.Ex: SOLAR POWER TOWERS
CO NTENTS
Introduction Global Issues Goals of green technology Solar Power Tower M ajor ajor Parts of Solar Power Po wer Tower Types of Solar Power Towers Solar One Solar Two Tres Solar Tower Land requirements System overview,benefits and impacts Power Scenario in India C onstraints onstraints References
IN TRODUCT TRODUCT I I ON:
Green is the way to go, so since we're in the age of technology, why not go green?In order to go with green technology , we need to fully understand what green technology is. Basically, green technology is that in which the technology is environmentally friendly friendly and is created and used in a way that conserves natural resources and the environment.We may hear green technology being referred referred to as environmental technology and clean technology. Green technology is a field of new, innovative ways to make changes in daily life. Currently, this Clean Technology is in the beginning stages of its development, so the future will only bring bigger and better things for this field. Green technology can be related to technological advances made in the field of power generation from non conventional energy source that are considered to be environmentally friendly and non polluting. p olluting. Every form of energy collection will result in some pollution but those that are green are known to cause less than those that are not.Green house gases ,a byproduct of traditional sources of energy such as fossil fuels are said to be causing global warming at an accelerated pace and hence there is a need to focus on technology that is environmentally friendly and also economically viable.
generation technologies are most competitive in locations with abundant resources.Their future depends on exploration of available resource potential particularly in developing countries and on overcoming challenges related to environment and social acceptance.
irst F irst
Example:-hydroelectric plants,geo thermal power plants and biomass briquettes.
Second generation technologies are said to be the future of power generation and is fast catching up but the market for these sources are limited to only a few countries.Example:- solar heating systems,use of ethanol,etc
Third generation technologies are not yet widely demonstrated or commercialised.They are on the horizon and may have potentional comparable to other renewable energy technologies but still depend on attracting suffecient attention and R&D funding.Ex:-Solar Power Tower
GLOBA L ISSUES:
The United Nations Energy Organization tags fossil fuels as elimentary energy/conventional energy.Electricity is merely a secondary energy derived from these sources.At present the energy consumed all over the world relies mainly on five main energy sources like coal,petroleum,natural coal,petroleum,natural gas,water and nuclear energy.The consumption of petroleum constitutes approximately 60% of energy used from all sources. Statistics show that daily consumption of petroleum is 40 million barrels of which 50% is for automobile use.In accordance with this calculation,as fuels are burnt poisonous materials such as 500 million
tonnes of carbon monoxide,100 million tonnes of hydrocarbons,550 million tonnes of carbon and 50 million tonnes of nitrogen oxides are emitted into atmosphere every year causing Green House Effect. The problems mentioned earlier can be addressed by implementing sustainable sources of energy.Sustainable energy sources are most often regarded as including all renewable energy sources like solar power,wind power,biofuels,wave energy,tidal energy and geothermal energy.
GOALS OF GREEN TECHNOLOGY:
Green technology is the future of this society. It's main goal is to find ways to produce technology in ways that do not damage or deplete the Earth's natural resources. In addition to not depleting natural resources, green technology is meant as an alternative source of technology that reduces fossile fuels and demonstrates less damage to human, animal, and plant health, as well as damage to the world, in general. Next, green technology is so that products can be re- used and recycled. The use of green technology (clean technology) is supposed to reduce the amount of waste and pollution that is created during production and consumption. The most important and urgent concern and want for green technology is for energy purposes. We need n eed better, more efficient was to produce energy without burning all the th e world's coal and using all the world's fossil fuels and natural resources.
OLAR TOWER
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Solar power towers also known as Concentrated Solar Power (CSP) Towers generate electric power from sunlight by focusing concentrated solar radiation on tower mounted heat exchangers. exchangers.
The system uses hundreds to thousands of sun-tracking mirrors called heliostats to reflect the incident sunlight onto the receiver. These plants are best suited for utility-scale applications in the 30 to 400 MW range.
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The limited supply of fossil hydrocarbon resources and the negative impact of CO2 emissions on the global environment dictate the increasing usage of renewable energy sources. Concentrated Solar Power (CSP) is the most likely candidate for providing the majority of this renewable energy, because it is amongst the most cost-effective renewable electricity technologies and because its supply is not restricted if the energy generated is transported from the world's solar belt to the population centres.
In power tower systems, heliostats (A Heliostat is a device that tracks the movement of the sun which is used to orient a mirror of field of mirrors, throughout the day, to reflect sunlight onto a target-receiver) reflect and concentrate sunlight onto a central tower-mounted receiver where the energy is transferred to a HTF. This energy is then passed either to the storage or to powerconversion systems, which convert the thermal energy into electricity. Heliostat field, the heliostat controls, the receiver, the storage system, and the heat engine, which drives the generator, are the major components of the system. For a large large heliostat field , a cylindrical cylindrical receiver receiver has advantages advantages when used with Rankine cycle engines, particularly for radiation from heliostats at the far edges of the field. Cavity receivers with larger tower height to heliostat field area ratios are used for higher high er temperatures required for the operation of turbines. These plants are defined by the options chosen for a HTF, for the thermal storage medium and for the power-conversion power-conversion cycle. HTF may be water/steam, molten nitrate salt, liquid metals or air and the thermal storage may be provided by PCM (phase change
materials) or thermally insulating materials.. Power tower systems usually achieves concentration ratios of 300±1500, can operate at o temperatures up to 1500 C. To maintain constant steam parameters even at varying solar irradiation, two methods can be used:
Integration of a fossil back-up burner; or
Utilization of a thermal storage as a buffer bu ffer
By the use of thermal storage, the heat can be stored for few hours to allow electricity production during periods of peak need, even if the solar radiation is not available.
Examples of heliostat based power plants: The 10 MWe Solar One and Solar Two demonstration projects in the Mojave Desert, which have now been decommissioned. d ecommissioned. y
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The above 10 MW Solar Tres Power Tower in Spain builds on these projects. In Spain the 11 MW PS10 Solar Power Tower was recently completed. In South Africa, a solar power plant is planned with 4000 to 5000 heliostat mirrors, each having an area of 140 m².
Major parts of solar tower are ± 1)Heliostats 2)Central Receiver 3)Molten Salt 4)Steam Generator
Heliostats:
Heliostats are reflective surfaces or mirrors which track the suns rays and reflect it onto the central receiver. Relatively few heliostats have been manufactured to date, and their cost is high (>$250/m2). As the demand for solar power increases, heliostat mass production methods will be developed that will significantly reduce reduce their th eir cost. Research is currently being conducted under the Solar Manufacturing Technology (SolMaT) Initiative to develop low-cost manufacturing techniques for early commercial low volume builds. Prices are a strong function of annual production rate. Since the heliostat field represents the largest single capital investment in a power tower plant, advancements in technology are needed to improve the ability to manufacture, reduce costs, and increase the service life of heliostats.
In particular, a lower cost azimuth drive system is needed (i.e., to rotate the heliostat around an axis that is perpendicular to the ground).
Recent Developments in Heliostat designs:
The modern R&D efforts have focused on polymer reflectors and stretched-membrane heliostats. A stretched-membrane heliostat consists of a metal ring, across which two thin metal membranes are stretched. A focus control system adjusts the curvature of the front membrane, which is laminated with a silvered-polymer reflector, usually by adjusting the pressure in the plenum between the two membranes.
Central Receiver:
Central receiver (or power tower) systems use a field of distributed di stributed mirrors ± heliostats ± that individually track the sun and focus the sunlight on the top of a tower. By concentrating the sunlight 600±1000 times, they achieve temperatures from 800°C to well over 1000°C.
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The central receiver is also called high-tech heat exchanger which sits atop a tower. tower. The central receiver heats molten salt at around 250°C, pumped from a ³cold´ storage tank, to 565°C, where it flows to a ³hot´ tank for storage. When the grid load dispatcher decides electricity is needed from the plant, hot salt is pumped to a steam generating system system that produces superheated steam for a turbine/generator. turbine/generator. The salt then is returned to the cold tank, where it is stored and eventually reheated in the receiver to complete the cycle.
Smaller, simpler receivers are needed to improve efficiency and reduce maintenance. Advanced receiver development currently underway, under the SolMaT Initiative, includes consideration of new steel alloys for the receiver tubes and ease of manufacture for the entire receiver subsystem. Panels of these new receiver designs were initially tested at Solar Two.
Molten Salt:
( MOLTEN SA MOLTEN SA LT S LT S TO TO RAG E SYS E SYS TEM) TEM)
Molten nitrate salt, though an excellent thermal storage medium, can be a troublesome fluid to deal with because of its relatively high freezing point (220oC/428ºF). To keep the salt molten, a fairly complex heat trace system must be employed. (Heat tracing is composed of electric wires attached to the outside surface of pipes. Pipes are kept warm by way of resistance heating.) Problems were experienced during the startup of Solar Two due to the improper installation of the heat trace. Though this problem has been addressed and corrected, research is needed reduce the the reliance reliance on heat tracing tracing in the plant.
This could be accomplished by one or more of the following options: ³anti-freeze´ to lower the th e freezing point, (1) develop a salt ³anti-freeze´ (2) identify and/or develop components that can be ³cold started´ without preapplication of the heat trace, or (3) develop thermal management practices that are less reliant on heat trace.
Within the Solar Two project, the third option will be explored. If it is unsuccessful, the other two options should be pursued. Also, valves can be troublesome in molten-salt service. Special packings must be used, oftentimes with extended bonnets, and leaks are not uncommon. Furthermore, freezing in the valve or packing can prevent it from operating correctly. While today¶s valve technology is adequate for molten-salt power towers, design improvements and standardization would reduce risk and ultimately reduce O&M costs. The salt storage medium is a mixture of 60 percent sodium nitrate and 40 percent potassium nitrate. It melts at 220ºC(428ºF) and is maintained in a molten state (290ºC/554ºF) in the µcold¶ storage tank. Molten salt can be difficult to handle h andle because it has a low viscosity (similar to water) and it wets metal surfaces extremely well. The energy storage system for Solar Two consists of two 875,000 liter storage tanks which were fabricated on-site by Pitt-Des Moines. The tanks are externally insulated and constructed of stainless steel and carbon steel for the hot and cold tanks, t anks, respectively. respectively. Thermal capacity of the system is 110 MWh . A natural convection cooling system is used in the foundation of each tank to minimize overheating and excessive dehydration of the underlying soil.
Steam Generator or turbines:
The steam generator design selected for the Solar Two project is completely different different than the prototype tested at Sandia Laboratories Laboratories during the technology development activity of the 1980¶s for Solar One because of change in heat transfer fluid. The recirculating-drum-type recirculating-drum-type system tested at Sandia performed performed well. However, However, at Solar Two, a kettle-boiler design was selected in an attempt to reduce cost. Significant problems have been encountered encountered with this new system during the startup phase at Solar Two, Two, requiring a redesign in many areas. Depending on the success of implementing the design changes, it was considered appropriate to reevaluate the optimum steam generator design before proceeding to the first commercial plant.
SOLAR TOWERS
YEAR OF COMISSION
Solar One
1982-1988
Solar Two
1996
Tres Solar Towers
PS10 - 2006 PS20 - 2009
SOLAR ONE:
Solar One, which operated from 1982 to 1988, was the world¶s largest power tower plant. It proved that large-scale power production with power towers was feasible. In that plant, water was converted to steam in the receiver and used directly to power a conventional Rankine-cycle steam turbine. The heliostat field consisted of 1818 heliostats of 39.3 m2 reflective area each. The project met most of its technical objectives by demonstrating -
(1) the feasibility of generating power with a power tower, (2) the ability to generate 10 MW for eight hours hou rs a day on summer solstice and four hours a day during winter solstice.
During its final year of operation, Solar One¶s availability during hours of sunshine was 96% and its annual efficiency was about 7%. (Annual efficiency was relatively low because of the plant¶s small size and the inclusion of non-optimized subsystems.)
The Solar One thermal storage system stored heat from solar produced steam in a tank filled with rocks and sand using oil as the heat-transfer fluid. The system extended the plant¶s powergeneration capability into the night and provided heat for generating low-grade steam for keeping parts of the plant warm during off-hours and for morning startup.
Unfortunately, the storage system was complex and thermodynamically inefficient. While Solar One successfully demonstrated power tower technology, it also revealed the disadvantages of a water/steam system, such as the intermittent
operation of the turbine due to cloud transcience and lack of effective thermal storage. During the operation of Solar One, research began on the more advanced molten-salt power tower design . This development culminated in the Solar Two project .
SOLAR TWO:
To encourage the development of molten-salt power towers, a consortium of utilities led by Southern California Edison joined with the U.S. Department of Energy to redesign the Solar One plant to include a molten-salt heat-transfer system. The goals of the redesigned plant, called Solar Two, are to validate nitrate salt technology, to reduce the technical and economic risk of power towers, and to stimulate the commercialization commercializat ion of power tower technology. techn ology. Solar one has produced 10 MW of electricity with enough thermal storage to continue to operate the turbine at full capacity for three hours after the sun has set. Long-term Long-term reliability was next to be proven. The conversion of Solar One to Solar Two required a new molten-salt heat transfer system (including the receiver, thermal storage, piping, and a steam generator) and a new control system. The Solar One heliostat field, the tower, and the turbine/generator required only minimal modifications. Solar Two was first attached to a utility grid in early 1996 and was scheduled to complete its startup phase in late 1997.
Solar Two construction and Design:
The panels form a cylindrical shell surrounding piping, structural supports, and control equipment. The external surfaces of the tubes are coated with a black Pyromark paint that is robust, resistant to high temperatures and thermal cycling, and absorbs 95% of the incident sunlight. The receiver design has been optimized to absorb a maximum amount of solar energy while reducing the heat losses due to convection and radiation.
The design, which includes laser-welding, sophisticated tubenozzle-header connections, a tube clip design that facilitates tube expansion and contraction, and non-contact flux measurement devices, allows the receiver to rapidly change temperature without being damaged. For example, during a cloud passage, the receiver can safely change from 290 to 570ºC (554 to 1,058ºF) in less than one minute.
The salt storage medium is a mixture of 60 percent sodium nitrate and 40 percent potassium nitrate. It melts at 220ºC(428ºF) and is maintained in a molten state (290ºC/554ºF) in the µcold¶ storage tank. Molten salt can be difficult to handle because it has a low viscosity (similar to water) and it wets metal surfaces extremely well.
Consequently, it can be difficult to contain and transport. An important consideration in successfully implementing this technology is the identification of pumps, valves, valve packing, and gasket materials that will work with molten salt.
Accordingly, Solar Two is designed with a minimum number of gasketed flanges and most instrument transducers, valves, and fittings are welded in place. p lace.
All pipes, valves, and vessels for hot salt were constructed from stainless steel because of its corrosion resistance in the molten-salt environment. The cold-salt system is made from mild carbon steel.
The steam generator system (SGS) heat exchangers, which were constructed by ABB Lummus, consist of a shell-and-tube superheater, a kettle boiler, and a shell-and-tube preheater.
Solar Two storage systems:
The energy storage system for Solar Two consists of two 875,000 liter storage tanks which were fabricated on-site by Pitt-Des Moines.
The tanks are externally insulated and constructed of stainless steel and carbon steel for the hot h ot and cold tanks, respectively. respectively.
Thermal capacity of the system is 110 MWh M Wh . A natural convection cooling system is used in the foundation of each tank to minimize overheating and excessive dehydration of the underlying soil.
Stainless steel cantilever pumps transport salt from the hot-tank pump sump through the SGS to the cold tank.
Salt in the cold tank is pumped with multi-stage centrifugal pumps up the tower to the receiver.
Tres Solar Tower
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These are the latest and technologically advanced solar towers towers with advanced designs built for commercial purpose generating more than 10 MW power. These were first built in Seville,Spain and named PS10 which produce around 11MW of power. After the success of this design ,a new and larger tower double the size of PS10 was constructed which was completed on 27 April,2009 which is a part of 300MW power project slated to be completed by 2013 . Its 16-hour molten-salt storage system will be able to deliver power around the clock.
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Costing around ¼1,200m, the whole plant will be completed by 2013, when it will produce around 300MW ± energy for around 180,000 homes, equivalent to the needs of the city of Seville. This will then prevent emissions of more than 600,000 tonnes of CO2 into the atmosphere per year over its 25-year life. The platform will create more than 1,000 jobs in the manufacturi manufacturing ng and construction phase, and 300 service and maintenance jobs.
Construction completed PS10 was completed at the end of 2006. y Work commenced on PS20 during the second half of 2006 y
Start of Operation March 2007 for PS10 y y
April 27,2009 for PS20
Location near Seville, Spain. y
Estimated Investment around ¼1,200m ¼1,200m for 300MW 300MW power power plant. y
Completition By 2013 y
PS10
The Solar Platform at Seville has been constructed by Solucar, using a range of solar technologies. The first solar power plant to be brought into operation was the PS10, the worl world's d's first commercial solar tower.
The 11MW PS10 solar power plant gener generates ates 24.3GW/hr per year of clean energy.
It has 624 heliostats that track the sun, each with a 120m² surface area parabolic mirror. mi rror.
The mirrors are focused on a 115m tower, heating water pipes that provide 200m² of waterwater-cooled cooled energy exchange surface area.
The thermal energy produces steam, which drives a turbine to generate electricity. During the day the power drives the air conditioners that cool buildings in Sevill Seville. e.
Heat is also stored as steam to allow generation at half load for an hour or longer after dark. This is a relatively short storage time, partially because the tower uses water rather than molten salt for heat storage.
The water is held in thermally clad tanks and reaches temperatures of 250°C ± 255°C (instead of around 600°C for systems using salt).
Solucar has opted for water to reduce fatigue on the system components and to ensure simplicity and robustness for the project.
PS20
PS20 has twice the PS10 output (20MW), with 1,255 two-axis sun tracking heliostats driving 120m² mirrors.
These mirrors concentrate solar radiation onto the receiver on top of a 165m tower. The tower follows the same technology as that of PS10 for electricity generation.
PS20 represents second generation technology with important improvements to receiver and other critical elements. Features include control and operational systems enhancements, improved thermal energy storage system and a higher efficiency receiver.
The tower can power about 10,000 homes and reduce 12,000 tonnes of CO2 emissions in comparison with conventional power plants. The plant has been designed by Abengoa Solar and Abener Energia was the contractor.
Land Requirement:
The following table shows the total surface needed to construct an installation. Besides area data needed (acres - hectares), width (x en ft) and length (y in ft) of the rectangular area.
20 MW
Basic Tower
Land requirement
235 acres y=10,826.77 ft x=3100 ft
System Overview, Benefits, and Impacts :
System Overview :
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New peaking and intermediate power sources are needed today in many areas of the developing world. India, Egypt, and South Africa are locations that appear to be ideally suited for power tower development. As the technology matures, plants with up to a 400 MW rating appear feasible.
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As non-polluting energy sources become more favored, molten-salt power towers will have a high value because the thermal energy storage allows the plant to be dispatchable. Consequently, the value of power is worth more because a power tower plant can deliver energy during peak load times when it is more valuable. Energy storage also allows power tower plants to be designed and built with a range of annual capacity factors (20 to 65%). Combining high capacity factors and the fact that energy storage will allow power to be brought onto the grid in a controlled controlled manner mann er (i.e., by reducing electrical transients thus increasing the stability of the overall utility grid), total market penetration is also much higher than an intermittent solar technology without storage or the use of solar panels. p anels.
Benefits of Solar Power T Power T owers owers :
Solar thermal power plants designed for solar-only generation are ideally matched to summer noon peak loads in prosperous areas with significant cooling demands, such as Spain or the south-western United States.
Thermal-energy storage in the power tower allows electricity to be dispatched to the grid when demand for power is the highest, thus increasing the monetary value of the electricity.
Much like hydro plants, power towers with salt storage are considered to be a dispatchable rather than an intermittent renewable energy power plant.
Besides making the power dispatchable, thermal storage also gives the power-plant designer freedom to develop power plants with a wide range of capacity factors to meet the needs of the utility grid. By varying the size of the solar field, solar receiver, and size of the thermal storage, plants can be designed with annual capacity factors ranging between 20 and 65%.
Economic studies have shown that levelized energy costs(LEC) are reduced reduced by adding more storage up to a limit of about 13hours (~65% capacity factor) . While it is true that storage increases the cost of the plant, it is also true that plants with higher capacity factors have better economic utilization of the turbine, and other balance of plant equipment.
Since salt storage is inexpensive, reductions in LEC due to increased utilization of the turbine more than compensates for the increased cost due to the addition of storage.
To increase capacity factor for a given turbine size, the designer would (1) Increase the number of heliostats, (2) Enlarge the thermal storage tanks, (3) Raise the tower, and (4) Increase the receiver dimensions.
Using thermal energy storage systems like the salt storage systems used in Solar Towers of Spain, solar thermal operating periods can even be extended to meet base-load needs needs or even during night.
Wherever there is high direct radiation from the sun, there are opportunities for solar thermal power generation especially the barren lands in deserts across the th e world.
In many regions of the world, just one square kilometre of land can generate as much as 100-130 gigawatt hours (GWh) of electricity per year from solar thermal technology.
This is as much electricity as we would expect from a 50 MW conventional coal- or gas-fired mid-load power plant, and enough to keep the lights on in a town of 25,000 inhabitants in western continental Europe.
Over the total life cycle of a solar thermal power system, output would be equivalent to energy contained in more than 5 million barrels of oil.
Impacts: y
No hazardous gaseous or liquid emissions are released during operation of the solar power tower plant. If a salt spill occurs, the salt will freeze before significant contamination of the soil occurs. Then the Salt is picked up with a shovel and can be recycled if necessary.
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If the power tower tower is hybridized hybridized with a conventional fossil plant like the use of additional gas turbines, emissions will be released from the non-solar portion of the plant.
One possible concern with the technology is the relatively high amount of land and water usage. This may become an important issue from a practical and environmental viewpoint since these plants are typically deployed within desert areas that often lack water and have fragile landscapes. Water usage at power towers is comparable to other Rankine cycle power technologies of similar size and annual performance and hence no much wastage as the water is recirculated. Land usage, although significant, is typically much less than that required for hydro and is generally less than that required for fossil (e.g., oil, coal, natural gas), when the mining and exploration of land are included.
Indian Power Scenario:
India ranks sixth in the world in total energy consumption.India has increased the installed capacity from 1362 MW 112058mw since independence.The achievement may be impressive but not sufficient.As many as 80000 villages are yet to be electrified and suffers power shortage of 12.3%.The annual per capita consumption of 580KWh is amongst the lowest in tthe he world.
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If the vast expanse of the Thar Desert in Northwestern India was harnessed to produce solar energy, it could light up five of Asia's most populated cities. Scientists say the endless sands of Rajasthan State could well earn the distinction of being the "biggest" solar powerhouse producing 10,000 MW of electricity. The Rajasthan Energy Development Agency (REDA) has started the spadework on an ambitious project. "A major chunk of the desert, about 13,500 square miles, will be declared a Solar Energy Enterprise Zone like the one in Nevada (in the United States)", says director Probhat Dayal. He thinks that if the state were to install solar collectors in just one Percent of its desert, which stretches over 77,200 square miles, "we could generate 6,000 megawatts of electricity". electricity".
Bottlenecks and Constraints in India:
(i) Renewable Energy Technologies are capital intensive and require high initial investment which investors could not mobilize in the th e absence of financial support including capital subsidy from the Central Government/ State Government. (ii) The power purchase policy has not been encouraging for private entrepreneurs and suitable policy initiatives in the form of wheeling, and banking facilities, evacuation, arrangements, land allotment etc., need to be considered to boost investment. (iii) Technologies for several renewable energy sources have not fully stabilized which has hampered the development and hence more intensive R&D efforts are called for with special focus on partnership with industry.
(iv) Fiscal incentives namely 100% depreciation attracted several private investors. But it has been diluted to a considerable extent by the imposition of Minimum Alternative Tax.
(v) Adequate number of professionally skilled manpower has not been developed in the renewable energy sector and hence training programmes may be organized to develop required manpower.
